170 citations · 1k across the 23 of their papers we have counts for
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The Advective Flux Transport Model: Improving the Far-Side with Active Regions observed by STEREO 304Å
Lisa A. Upton, Ignacio Ugarte-Urra, Harry P. Warren +1
Observations the Sun's photospheric magnetic field are often confined to the Sun-Earth line. Surface flux transport (SFT) models, such as the Advective Flux Transport (AFT) model,…
Assessing the Performance of the ADAPT and AFT Flux Transport Models Using In-Situ Measurements From Multiple Satellites
Kalman J. Knizhnik, Micah J. Weberg, Elena Provornikova +7
The launches of Parker Solar Probe (Parker) and Solar Orbiter (SolO) are enabling a new era of solar wind studies that track the solar wind from its origin at the photosphere, thro…
Solar Cycle Observations
Aimee Norton, Rachel Howe, Lisa Upton +1
We describe the defining observations of the solar cycle that provide constraints for the dynamo processes operating within the Sun. Specifically, we report on the following topics…
Solar Cycle Precursors and the Outlook for Cycle 25
Lisa A. Upton, David H. Hathaway
Sunspot Cycle 25 over 3 years past the cycle minimum of December 2019. At this point, curve-fitting becomes reliable and consistently indicates a maximum sunspot number of 135+/-10…
Physical Models for Solar Cycle Predictions
Prantika Bhowmik, Jie Jiang, Lisa Upton +2
The dynamic activity of stars such as the Sun influences (exo)planetary space environments through modulation of stellar radiation, plasma wind, particle and magnetic fluxes. Energ…
Variations in Differential Rotation and Meridional Flow within the Sun's Surface Shear Layer 1996-2022
David H. Hathaway, Lisa A. Upton, Sushant S. Mahajan
We measure differential rotation and meridional flow in the Sun's surface shear layer by tracking the motions of the magnetic network seen in magnetograms from SOHO/MDI and SDO/HMI…
Determining the source and eruption dynamics of a stealth CME using NLFFF modelling and MHD simulations
Stephanie L. Yardley, Paolo Pagano, Duncan H. Mackay +1
Coronal mass ejections (CMEs) that exhibit weak or no eruption signatures in the low corona, known as stealth CMEs, are problematic as upon arrival at Earth they can lead to geomag…
Investigation of the Middle Corona with SWAP and a Data-Driven Non-Potential Coronal Magnetic Field Model
Karen A. Meyer, Duncan H. Mackay, Dana-Camelia Talpeanu +2
The large field-of-view of the Sun Watcher using Active Pixel System detector and Image Processing (SWAP) instrument on board the PRoject for Onboard Autonomy 2 (PROBA2) spacecraft…
Hydrodynamic Properties of the Sun's Giant Cellular Flows
David H. Hathaway, Lisa A. Upton
Measurements of the large cellular flows on the Sun were made by local correlation tracking of supergranules seen in full-disk Doppler images obtained by the HMI instrument on the…
An Updated Solar Cycle 25 Prediction with AFT: The Modern Minimum
Lisa A. Upton, David H. Hathaway
Over the last decade there has been mounting evidence that the strength of the Sun's polar magnetic fields during a solar cycle minimum is the best predictor of the amplitude of th…
Global Non-Potential Magnetic Models of the Solar Corona During the March 2015 Eclipse
A. R. Yeates, T. Amari, I. Contopoulos +17
Seven different models are applied to the same problem of simulating the Sun's coronal magnetic field during the solar eclipse on 2015 March 20. All of the models are non-potential…
The Extended Solar Cycle: Muddying the Waters of Solar/Stellar Dynamo Modeling Or Providing Crucial Observational Constraints?
A. K. Srivastava, S. W. McIntosh, N. Arge +17
In 1844 Schwabe discovered that the number of sunspots increased and decreased over a period of about 11 years, that variation became known as the sunspot cycle. Almost eighty year…
Modeling Coronal Response in Decaying Active Regions with Magnetic Flux Transport and Steady Heating
Ignacio Ugarte-Urra, Harry P. Warren, Lisa A. Upton +1
We present new measurements of the dependence of the Extreme Ultraviolet radiance on the total magnetic flux in active regions as obtained from the Atmospheric Imaging Assembly (AI…
Predicting the Amplitude and Hemispheric Asymmetry of Solar Cycle 25 with Surface Flux Transport
David H. Hathaway, Lisa A. Upton
Evidence strongly indicates that the strength of the Sun's polar fields near the time of a sunspot cycle minimum determines the strength of the following solar activity cycle. We u…
Magnetic Flux Transport and the Long-Term Evolution of Solar Active Regions
Ignacio Ugarte-Urra, Lisa Upton, Harry P. Warren +1
With multiple vantage points around the Sun, STEREO and SDO imaging observations provide a unique opportunity to view the solar surface continuously. We use He II 304 A data from t…
Magnetic Flux Transport at the Solar Surface
J. Jiang, D. H. Hathaway, R. H. Cameron +3
After emerging to the solar surface, the Sun's magnetic field displays a complex and intricate evolution. The evolution of the surface field is important for several reasons. One i…
Effects of Meridional Flow Variations on Solar Cycles 23 and 24
Lisa Upton, David H. Hathaway
The faster meridional flow that preceded the solar cycle 23/24 minimum is thought to have led to weaker polar field strengths, producing the extended solar minimum and the unusuall…
The Solar Meridional Circulation and Sunspot Cycle Variability
David H. Hathaway, Lisa Upton
We have measured the meridional motions of the magnetic elements in the Sun's surface layers since 1996 and find systematic and substantial variations. In general the meridional fl…
Giant Convection Cells Found on the Sun
David H. Hathaway, Lisa Upton, Owen Colegrove
Heat is transported through the outermost 30% of the Sun's interior by overturning convective motions. These motions are evident at the Sun's surface in the form of two characteris…
Predicting the Sun's Polar Magnetic Fields with a Surface Flux Transport Model
Lisa Upton, David H. Hathaway
The Sun's polar magnetic fields are directly related to solar cycle variability. The strength of the polar fields at the start (minimum) of a cycle determine the subsequent amplitu…